Browsing by Author "Baylan, Elif"

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Hidrotermal Yöntemle Sentezlenen Çinko Stanat (zn2sno4) Nanoparçacıkların Fotokatalitik Performanslarının İncelenmesi
(2019) Baylan, Elif; Culu, Ayşe; Yıldırım, Mehmet Serdar; Öztürk, Teoman; Sönmezoğlu, Savaş; Altıntaş Yıldırım, Özlem
Çinko stanat (Zn2SnO4, ZTO) nanoparçacıklar hidrotermal yöntemle 180 °C ve 24 saatte başarılı bir şekilde sentezlenmiştir. Sentezlenen nanoparçacıkların yapısal, morfolojik ve optik özellikleri X-ışını kırınımı, Taramalı elektron mikroskobu (SEM), Fourier Dönüşümlü Infrared Spektrofotometre spektrumu ve UV-Visible spektroskopisi ile karakterize edilmiştir. X-ışını kırınım methodu sonucunda elde edilen pik desenleri incelendiğinde sentezlenen yapının ters kübik spinel formda oluştuğu ve ortalama kristal boyutunun ~22 nm olduğu belirlenmiştir. SEM görüntüleri, sentezlenen nanoparçacıkların küresel morfolojide oluştuğunu göstermektedir. Aynı zamanda sentezlenen Zn2SnO4 nanoparçacıkların Rodamin B (RhB) boyar maddesinin bozunumuna karşı davranışı UV ve görünür ışık altında incelenmiştir. 180 dakikalık yüksek şiddetli UV ışığına maruz bırakılma sonucunda RhB boya çözeltisinin % 82’si bozunurken daha düşük enerjili görünür ışık altında 420 dakikalık ışıma sonucunda da % 86’sının bozunduğu gözlemlenmiştir.
Citation - WoS: 49
Citation - Scopus: 54
Highly Efficient Photocatalytic Activity of Stable Manganese-Doped Zinc Oxide (mn:zno) Nanofibers Via Electrospinning Method
(ELSEVIER SCI LTD, 2019) Baylan, Elif; Altıntaş Yıldırım, Özlem
Manganese-doped zinc oxide (Mn:ZnO) nanofibers were synthesized using the electrospinning process. Structural, chemical, morphological and optical properties of the nanofibers were characterized and compared with undoped ZnO nanofibers. To investigate photocatalytic activity of nanofibers under the both UV and visible light, methylene blue (MB) was used as a representative dye pollutant. It was found that substitutional incorporation of Mn2+ and Mn4+ ions in ZnO resulted in the generation of additional energy levels within the band gap of ZnO. Furthermore, higher manganese incorporation resulted in smaller-sized Mn:ZnO nanoparticles with highly concave-convex structures, and consequently, an increase in surface area. Substitutional incorporation of the dopant ions and the resulting morphological variations provide better photocatalytic efficiency due to formation of a greater number of charge carriers and the corresponding delay in the recombination process. Among the studied dopant content, 0.5 at.% Mn:ZnO fibers was determined as the optimal composition and the degradation of MB can reach about similar to 100% after 90 min. UV light and similar to 35% after 100 min visible light illumination. The doped fibers displayed high stability and durability in the degradation tests, even after ten cycles. Mn:ZnO nanofibers are thus good candidate materials for photocatalytic applications with superior efficiencies and highly reusable properties.
Citation - WoS: 9
Citation - Scopus: 9
Stable Cucro2 Nanoparticles - Zno Fibres P-N Heterostructure System for Effective Photocatalytic Activity
(UNIV NOVI SAD, FAC TECHNOLOGY, 2019) Baylan, Elif; Akyıldız, Hasan; Altıntaş Yıldırım, Özlem
Heterostructured photocatalysts were fabricated by coupling electrospunn-type ZnO fibres and hydrothermally derived p-type CuCrO2 nanoparticles. The effect of the amount of CuCrO2 nanoparticles on the photocatalytic activity of the heterostructured photocatalyst was systematically investigated. The formation of the heterojunctions between the two semiconductors was revealed via detailed XRD, XPS, TEM and optical property measurements. The experimental results indicated that the optimal CuCrO2 amount in the composite photocatalyst was 1.0 wt.% due to the optimum doping and surface coverage, higher absorption onset edge, larger absorption intensity and optimum band gap energy. This composite photocatalyst, fabricated by drop casting of CuCrO2 nanoparticle dispersion on ZnO fibres, displayed 30% higher rate constant (k) value compared to the pure ZnO fibres in the degradation of methylene blue dye molecules and reached 93.4% decomposition in 1 h under UV-visible light exposure. The obtained results are highly encouraging in comparison to only UV/light active p-n heterostructured photocatalysts previously reported in literature. Therefore, we believe that the proposed approach here opened the way for simple synthesis of highly-efficient visible light active heterostructured semiconductor photocatalyst systems.